Natural selection became one of the most contentious parts of Darwin’s theory of evolution, in part because of its source.41 However, Darwin’s unexpected move was not in relying on Malthus’s law of population; it was in turning it from a barrier to progress into progress’s driving engine. Natural selection at long last solved the problem of what was the underlying structure of all natural history—indeed of life. For Darwin, the process is the structure. He had turned nature’s most obvious characteristic, its propensity for change, into its greatest virtue.
